The invention relates to a fastening arrangement for a movable part, especially a folding top or a roof, of a motor vehicle, with a rotary latch which serves for securing a fastening pin of the movable part and is rotatable by means of an actuating device for a blocking and release of the fastening pin and which can be retained by means of a detent pawl and is rotatable oppositely to the blocking direction of the detent pawl.
Such a fastening for a motor-vehicle tailgate is known from German Patent Document DE 3,801,581 C1. In this arrangement during the movement of opening the tailgate the detent pawl is pivoted into a release position not blocking the rotary latch, until the rotary latch has passed the preclosing position. Since the detent pawl does not block the rotary latch during this movement, the latter is also rotatable oppositely to the blocking direction of the detent pawl, for example as a result of pressure on the tailgate.
A fastening for a motor-vehicle folding top is known from German Patent Document DE 3,708,095 C2. With the folding-top fastening in the locked position, the rotary latch secures the fastening pin and is locked by means of the detent pawl engaging into its principal notch. Relatively high frictional forces between the rotary latch and detent pawl occur in this position as a result of the undercut in the principal notch of the rotary latch. During the unlocking of the fastening, the direction of movement of the rotary latch is reversed when the detent pawl is being shifted out at the mouth of the principal notch, the fastening at least partially unlocking itself as a result of the prestress caused by sealing forces. This reversal of movement can lead to noises during the release of the lock.
It is also known from German Patent Document DE 3,126,810 C2, in a motor-vehicle door fastening, to shift the detent pawl out by means of a control cam arranged on the rotary latch, in order to prevent knocks caused by impact.
An object of the invention is to provide a fastening arrangement of the type mentioned above, by means of which frictional forces and noises occurring during the operation of opening the movable part are reduced.
This object is achieved according to preferred embodiments of the invention in that there is a lever mechanism which can be activated by the actuating device and which positively guides the rotational movement, including a rotation opposite to the blocking direction of the detent pawl, of the rotary latch during the operation of opening and locking the movable part.
Contact between rotary latch and detent pawl is thereby largely eliminated during the operation of opening and locking the movable part, with the result that virtually no frictional forces occur any more between rotary latch and detent pawl. The wear of the parts of the fastening is consequently greatly reduced. Furthermore, the disturbing noises which occur in the state of the art during the operation of opening or closing the fastening and which were generated by the sudden reversal of the direction of movement of the rotary latch when the detent pawl was being shifted out are also prevented.
In a further embodiment of the invention, the lever mechanism has a control cam rotatable about the axis of rotation of the rotary latch and connected to the actuating device, and a rocker lever connected by means of a first slotted guide to the control cam and by means of a further slotted guide to pivotable driver and pivotable about an axis parallel to the axis of rotation. The mechanics of the lever mechanism are thus set in motion by the actuating device, so that the control of the rotary latch begins with the initiation of the opening operation by the actuating device.
In a further embodiment, the driver is connected by means of a slotted guide to an engagement point of the rotary latch located opposite the detent pawl. Consequently, by means of the driver the lever mechanism can impart to the rotary latch a pivoting opposite to the blocking direction between detent pawl and rotary latch.
In a further embodiment of the invention, the driver is prestressed against the rocker lever by means of a spring. Since the driver bears on the rocker lever, any control movement of the control cam is transmitted to it and therefore, via the engagement point, to the rotary latch.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.